Prosze o pomoc !! :) dam naaj !: D
e ){1/2 - 3 /4 y = 0
2/3x + 1 1/4 y = 9
f ) { 3 x + 4 y = 1 2/3
6x + 3y = 1 1/4
Temat : Rozwiazywanie układów równań metoda podstawiania
Jak cos to macie strone ksiażki Zadanie 9 str 93 ( starsza wersja ) zadanie 9 str 99 ( nowsza ) KLASA 2 GIM ; )
Odpowiedzi
e)
1/2 - 3/4y = 0 |*4
2/3x + 1 1/4y = 9 | *12
2 - 3y = 0
8x + 15y = 108
3y = 2 |:3
8x + 15y = 108
y = 2/3
8x + 15 * 2/3 = 108
y = 2/3
8x + 10 = 108
y =2/3
8x = 108 - 10
y = 2/3
8x = 98 |:8
y = 2/3
x = 12 1/4
sprawdzenie:
1/2 - 3/4 * 2/3 = 1/2 - 1/2 = 0
0=0
2/3 * 12 1/4 + 1 1/4 * 2/3 = 2/3 * 49/4 + 5/4 * 2/3 = 49/6 + 5/6 = 54/6 = 9
9=9
Odp: x = 12 1/4 y = 2/3
f)
3x + 4y = 1 2/3 |*3
6x + 3y = 1 1/4 |*4
9x + 12y = 5
24x + 12y = 5
12y = 5 - 9x
24x + 5 - 9x = 5
12y = 5 - 9x
15x = 0 |:15
12y = 5 - 9x
x = 0
12y = 5 - 9 * 0
x = 0
12y = 5 - 0
x = 0
12y = 5 |:12
x = 0
y = 5/12
x = 0
sprawdzenie:
3 * 0 + 4 * 5/12 = 0 + 5/3 = 5/3 = 1 2/3
1 2/3 = 1 2/3
6 * 0 + 3 * 5/12 = 0 + 5/4 = 5/4 = 1 1/4
1 1/4 = 1 1/4
Odp: x = 0, y = 5/12
f)
3x+4y=1 2/3
6x+3y=1 1/4
3x-4y=5/3 I *(-2)
6x+3y=5/4
-6x+8y=-10/3=-40/12
6x+3y=5/4=15/12
11y=-25/12I :11
y=-25/12/11
e)
1/2x-3/4y=0I*5
2/3x+5/4y=9I*(-3)
5/2x-15/4y=5
-6/3x-15/4y=-27
3/6x=-22
x=-22/1/2
x=-11
